| 摘要 |
PROBLEM TO BE SOLVED: To provide a vehicle control unit making it possible to shorten a delay in a response to shift to a four-wheel drive state when a four-wheel drive shift condition is satisfied during turning of a vehicle whose front and rear wheels can be steered.SOLUTION: A front-wheel cornering drag and a rear-wheel cornering drag in a 4WS (Four-Wheel Steering) vehicle are estimated. As the rear-wheel drag, a larger value is estimated when steering directions of the front and rear wheels are in phase with each other than when the steering directions are out of phase from each other. A vehicle body deceleration is estimated from the estimated cornering drag forces, and electronically controlled couplings are controlled so that a pre-torque which is set to be larger as the vehicle body deceleration is higher is applied to the rear wheels during turning acceleration of the vehicle. The pre-torque is applied to the rear wheels, and when a condition for shift to a four-wheel drive state is satisfied later, the shift to the four-wheel drive state is immediately completed. |
